1. Field of the Invention
This invention relates generally to electrical connectors, and more particularly, to a mounting for a pair of spaced lamp holders or receptacles for receiving double-ended gaseous discharge lamps of the fluorescent type.
2. Description of the Prior Art
To facilitate mounting of a fluorescent electrical fixture, it is current practice to provide lamp holders (or receptacles) in sets or pairs, with one of the lamp holders being stationarily mounted or substantially so, and the other being axially compressible to a substantial degree, to facilitate the insertion of the lamp ends in the lamp holders. After insertion of the lamp ends in the lamp holders, the compressible lamp holder exerts an axial pressure upon the lamp, causing it to tightly engage at its respective ends in the lamp holders of the set.
The lamp holders are mounted on spaced mounting plates, usually by means of a spring clip. Typical of lamp holder patents illustrating the lamp holders and their mountings are Kulka, U.S. Pat. No. 3,116,098 issued Dec. 21, 1963, and Genovese et al., U.S. Pat. No. 3,681,593 issued Aug. 1, 1972. In both of these patents, the compressible lamp holder is of the snap-in type, that is to say, the lamp holder is equipped with a spring clip that permits the lamp holder to be snapped into a mounting panel as a labor-saving expedient. Further, such spring clip mountings facilitate the release of the lamp holder from the mounting panel from the front of the panel, which is desirable, for example, if the lamp holder should malfunction or should otherwise become faulty in operation. While the metal spring clips of both Kulka and Genovese et al. accomplish these functions, they do present other drawbacks.
Specifically, in Kulka, the metal spring clips for attaching the lamp holder to the mounting panel is connected to the lamp holder by means of rivets which extend through aligned openings or apertures in the front face of a mounting flange of the lamp holder to the rear surface of the flange. It has been found that if the lamp holder is mounted outdoors, water can accumulate in the aperture housing the rivet and there is a substantial chance that an electrical short can develop to ground through the face rivet and metal mounting clip. Accordingly, it is necessary to eliminate the spring clip mounting wherein it is attached by rivets to the face of the lamp holder. Genovese et al. accomplishes this by providing a one-piece spring metal mounting clip which is mounted to the rear of the lamp holder by a threaded fastener, thus eliminating the need to mount separate spring legs by rivets to the face of the lamp holder flange. However, it is still possible to develop an electrical short to ground through the spring metal clip, particularly where the lamp holder is compressible against the mounting plate through use of a coil spring surrounding the lamp holder between the metal plate and the flange of the lamp holder. The coil spring is virtually in contact with or slightly spaced from the end of the metal mounting clip and provides a spark gap which can be crossed to short the lamp to ground. Further, although the lamp holder is formed from an electrical insulative material, such as molded plastic or the like, it has been found that current can migrate through the lamp holder to the metal clip to ground to form an electrical short to ground discharging the lamp mounted to the lamp holder.